Since various kinds of equipment such as electric vehicles and hybrid electric vehicles require power sources having large capacity, there is provided a battery pack including a plurality of battery cells 6 as shown in FIG. 10 (see Japanese Unexamined Patent Application Publication No. 2008-181765, for example).
As shown in FIG. 11, the plurality of battery cells 6 each has a prismatic exterior case 60 and a pair of electrode terminals 61 protruding from an upper face of the exterior case 60.
The electrode terminals 61 each have a bent piece 610 formed by bending a plate-like member. The bent piece 610 has a first piece 611 protruding upward from the exterior case 60 and a second piece 612 extending from the first piece 611 and extending in a direction orthogonal to a direction in which the first piece 611 extends. A coupling hole 613 is formed in the second piece 612.
In the battery pack, the second pieces 612 of the adjacent battery cells 6 are brought into contact with each other and the battery cells 6 are electrically connected to each other. Further, in the battery pack, a fastening member such as a rivet and a bolt (a rivet in the case of the battery pack shown in FIG. 12) is inserted into the coupling hole 613 of each of the second pieces 612 being in contact with each other. Then, the second pieces 612 being in contact with each other are fastened to each other by the fastening member.
Hence, in the case of manufacturing the battery pack, when the fastening member is inserted into the coupling hole 613 of each of the second pieces 612 of the adjacent battery cells 6, it is necessary to align the coupling holes 613 of the second pieces 612 with each other. Therefore, the work of electrically connecting the adjacent battery cells 6 is complicated.
Moreover, in the battery pack, when the second pieces 612 of the adjacent battery cells 6 are not properly fastened to each other, connection between the second pieces 612 of the adjacent battery cells 6 is occasionally released. Hence, electrical connection between the adjacent battery cells 6 is occasionally released.
In the battery pack, a terminal connected to an external circuit (a circuit that electricity flows through partially and that constitutes a part of an electric circuit, such as a motor, a control unit, or another battery pack) is fastened to each of the electrode terminals 61 of the battery cell 6, for example. Also in this case, when the terminal is not properly fastened to the electrode terminals 61 of the battery cell 6, connection between the electrode terminals 61 of the battery cell 6 and the terminal is occasionally released. Hence, electrical connection between the external circuit and the battery cell 6 is occasionally released.